At Robotic Research Centre (RRC) in Nanyang Technological University,
the Remotely-Operated Vehicle (ROV) for underwater pipeline tracking was
designed. The RRC ROV is tethered by a 100 m long
cable that supplies 230 VAC electrical powers through an AC generator (powered
by gasoline). The umbilical cable dispensed from the tether drum provides the
communication and video signal lines for the RS-485 standard at a
baud rate of 9600. The control system
embedded inside the ROV consists of one industrial controller (incorporates an
AMD 5x86-133 processor with 6 MB RAM), thrusters’ driver, navigation module and
two cameras that were hosted on a QNX real-time operating system (QNX-RT OS).

Non-linear Observer Results: Due to the
limitation of on-board sensors at the time of the test, only simple tests
for yaw and heave operation (pressure
and magnetic compass sensor respectively) were taken. The experiment results were compared with the nonlinear
observer. The remaining unmeasured
surge and sway positions were obtained through the nonlinear observers.

The nonlinear observer was able to estimate the heading and altitude. The
magnetic compass for yaw angle was initially at 360 degrees angle before
correcting itself to the zero degree angle. It took almost ten seconds for the correction to complete. The observer
was able to estimate the desired squared profile with small estimated error
withsome oscillations in the surge and sway position
as the vehicle maneuvered a 90 degrees turn. This effect was contributed by the
wave reflected from the pool walls.

-Preparing for the pool test at NTU.

-Launching ROV to pool.

-RRC ROV experimental setup near pool.

b) ROV -Temasek Polytechnic and DHI.

On 18 November 2009,
the ROV project group went for a sea trial at Pulau Hantu.